1. Field of the Invention
The present invention relates to an optical film, a polarizing plate, an image display, and a manufacturing method of the optical film.
2. Description of Related Art
In recent years, toughness is required of displays on handling by general users in homes. For example, in various image displays such as a liquid crystal display (LCD), a plasma display panel (PDP), electroluminescence display (ELD), cathode ray tube display (CRT), SED (Surface-Conduction Electron-Emitter Display), the optical films used on the surfaces thereon are required to have high physical strength (scratch resistance and the like), transparency, chemical resistance, and weather resistance (moisture and heat resistance, light fastness and the like). For preventing the reduction of contrast by the reflection of outer light and mirroring of images, antiglare and antireflection properties are also required of optical films. An antifouling property and a dust preventing property of the surface that dirt and dust are difficultly adhered by daily handling are also required.
As materials showing a high hard coat property, photosensitive resin compositions for a hard coat agent containing a reaction product of a mixture of dipentaerythritol, tripentaerythritol and tetrapentaerythritol, with (meth)-acrylic acid are disclosed in JP-A-2002-235018. Although these materials have a certain effect, further increase in hardness and reduction of curling are required.
A layered product improved in alkali resistance by providing a clear hardening resin layer on an antiglare layer is disclosed in JP-A-2004-50535. The layered product is also improved in light fastness and moisture and heat resistance by forming an optical thin film on the laminate by vacuum deposition. The layered product shows certain scratch resistance, but further improvement is desired supposing the use on the surface of displays.